Two cars are traveling in the same direction along the same route

Two cars are traveling in the same direction along the same route. The red car travels at a constant speed of 40 miles per hour, and the black car is traveling at a constant speed of 50 miles per hour. If the red car is 30 miles ahead of the black car, how many hours will it take the black car to overtake the red car?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #17694